Hearing aid



FIG. 1 is a side elevational view of a hearing aid showing my new design;

FIG. 2 is a side elevational view thereof taken from the right of FIG. 1;

FIG. 3 is a side elevational view thereof, taken from the left of FIG. 1;

FIG. 4 is a top plan view thereof; and

FIG. 5 is a bottom plan view thereof. 

The ornamental design for a hearing aid, as shown and described. 